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> Forsiden > Publikationer > Geology of Greenland Survey Bulletin > Vol. 191 Geol. Greenl. Surv. Bull. > Review of Greenland Activities 2001, pp 117-125

GEOLOGY OF GREENLAND SURVEY BULLETIN 191

 
Lower…Middle Ordovician stratigraphy of North-East Greenland

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The Upper Proterozoic (Riphean) to Lower Palaeozoic
succession in North-East Greenland is exposed in a
broad N­S-trending belt in the fjord region between
71°38´ and 74°25´N (Fig. 1). The succession comprises
mainly marine sediments accumulated during the later
stages of the break-up of the Rodinia supercontinent,
the subsequent opening of the Iapetus Ocean and for-
mation of the passive margin along the edge of the
Laurentian palaeocontinent.
Investigations of the sedimentary succession were ini-
tiated on Ella Ø in the summer of 2000 as part of a pro-
ject to investigate the development of the Laurentian
margin facing the Iapetus Ocean in the Early Palaeozoic,
when studies of the uppermost formations of the
Riphean Eleonore Bay Supergroup to the Lower
Ordovician Antiklinalbugt Formation on Ella Ø were
undertaken (Stouge et al. 2001). Ella Ø was revisited
during the summer of 2001, with the focus on the
Ordovician formations. In addition, investigations were
undertaken in the Albert Heim Bjerge area where the
uppermost part of the Ordovician succession is preserved
(Fig. 1).
The scientific station at Solitærbugt on Ella Ø (Fig. 1)
was used as the operational base, and helicopter sup-
port allowed the establishment of camps on the plateau
of Ella Ø and in the Albert Heim Bjerge area.
Ella Ø
Ella Ø preserves exposures of the uppermost part of
the Riphean Eleonore Bay Supergroup and the whole
of the Vendian Tillite Group, while the Lower Palaeozoic
sequence ranges from the Lower Cambrian to the lower
Middle Ordovician (Fig. 2; Poulsen 1930; Poulsen &
Rasmussen 1951; Cowie & Adams 1957; Hambrey 1989).
This succession is unconformably overlain by Devonian
continental aeolian and fluviatile clastic rocks.
The main aims of the work on Ella Ø in 2001 were
to carry out detailed stratigraphic logging of the upper
Lower Ordovician Cape Weber Formation and the lower
Middle Ordovician Narwhale Sound Formation, to col-
lect samples for biostratigraphical control throughout
the succession in order to constrain the duration of the
major hiatus recorded in the Lower Ordovician part of
the succession, and to define the lithological bound-
aries between the recognised units.
Excellent exposures of the Lower to Middle Ordo-
vician strata are found on the 500­900 m high central
plateau of Ella Ø (Fig. 1, section 4; Fig. 3) and along
the steep cliffs around Antiklinalbugt (Fig. 1, section 5;
Fig. 4) which were reached from the base camp using
a rubber dinghy.
The overall succession through the stratigraphic inter-
val of the upper Canadian Series (Lower Ordovician)
and into the lower Whiterockian (Middle Ordovician)
is a conformable, shallowing-upward carbonate suc-
cession that begins disconformably above the silty,
dolomitic beds forming the top of the Antiklinalbugt
Formation (Figs 2, 4).
Cape Weber Formation
The basal contact of the Cape Weber Formation is placed
at the top of the dolomitic beds mentioned above. The
upper boundary of the Cape Weber Formation is placed
at the appearance of the finely laminated, light grey,
yellow-weathering dolostone and dolomitic limestone
of the overlying Narwhale Sound Formation.
Cowie & Adams (1957) subdivided the Cape Weber
Formation on Ella Ø into a lower `Banded Limestones',
the `Main Limestones' and the upper `Dolomites and
Dolomitic Limestones'. In this study the formation has
been measured to be 1140 m thick on Ella Ø, and four
informal mappable lithological units are distinguished:
units A­D. Unit A and the lower part of Unit B corre-
spond to the `Banded Limestones', Unit C is equivalent
to the `Main Limestones' and Unit D comprises the
upper part of the `Main Limestones' and the `Dolomites
and Dolomitic Limestones' of Cowie & Adams (1957).
117
Lower­Middle Ordovician stratigraphy of North-East
Greenland
Svend Stouge,W. Douglas Boyce, Jørgen L. Christiansen, David A.T. Harper and Ian Knight
Geology of Greenland Survey Bulletin 191, 117­125 (2002) © GEUS, 2002
GSB191-Indhold 13/12/02 11:32 Side 117
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Unit A
Unit A is 100 m thick. The sequence is made up of
metre-thick carbonate beds composed of domal to
broad, flat stromatolitic and thrombolitic mounds (Fig. 5),
laminated lime mudstone and dolostone, intraclastic
limestones, minor chert nodules and white-weathering
silty interbeds.
The macrofauna recorded from the unit includes
trilobites, cephalopods and gastropods. The lower inter-
val is characterised by the trilobite Peltabellia sp. whereas
the higher part of Unit A is referred to the Strigigenalis
brevicauda Zone (Boyce 1989; Boyce & Stouge 1997).
These two faunal intervals represent the Jeffersonian
Stage of the Canadian Series. The sparse conodont
fauna (Smith 1991) is included in the comprehensive
Fauna D of Ethington & Clark (1971). Smith (1991) had
118
4
5
Bastionen
Bastionbu
gt
Soli
tærb
ugt
Antiklinalbugt
10 km
10 km
Fimbulfje
ld
Ella Ø
Base camp
Measured section
ELLA Ø / ALBERT HEIM BJERGE
Devonian
continental sediments
Quaternary
Ordovician
marine sediments
Cambrian
fluviatile and marine sediments
Vendian, Tillite Group
tillites and marine sediments
Riphean, Eleanore Bay Supergroup
marine sediments
Inland Ice
Kong Oscar Fjor
d
74
°
21
°
21
°
27
°
27
°
72
°
74
°
Traill Ø
Mestersvig
Palaeogene igneous rocks
East Greenland Basin
Carboniferous­Cretaceous
sediments
POST-CALEDONIAN
Crystalline rocks
Greenland shield
CALEDONIAN FORELAND
Thrust
Fault/shear zone
Caledonian granites
Neoproterozoic­Ordovician
sediments
CALEDONIAN OROGENIC BELT
Crystalline complexes
(Archaean­Mesoproterozoic)
Devonian
continental sediments
LATE TO POST-CALEDONIAN
Kejser FranzJosephFjord
Ymer Ø
Kap
Weber
C. H. Ostenfeld Nunatak
Albert Heim Bjerge
Albert Heim
Bjerge
Ella Ø
Wordie Gletcher
Promenadedal
50 km
Albert Heim
Bjerge
Reservatet
Vibeke Elv
6
Greenland
Fig. 1. Locality map of North-East Greenland with simplified geology. The inset maps of Ella Ø and Albert Heim Bjerge show loca-
tions of the investigated sections 4, 5 and 6. Geology modified from Cowie & Adams (1957) and Henriksen (1999).
GSB191-Indhold 13/12/02 11:32 Side 118
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119
Fig. 2. The upper Lower to Middle Ordovician stratigraphy of North-East Greenland compared to trilobite zones of Utah, USA and
western Newfoundland, Canada.
System
Or
do
vician
Canadian
Lo
w
e
r
Whiter
ockian
Mid
dle
Series
North-East Greenland
Formations
informal units
Heimbjerge
Narwhale Sound
Narwhale
Sound
Cape
Weber
Cape
Weber
Hiatus
Hiatus
Antiklinalbugt
?
Antiklinalbugt
Ella Ø
Albert Heim
Bjerge
W. Newfoundland
Trilobite
zones
Boyce & Stouge (1997)
Strigigenalis
brevicaudata
Randaynia
saundersi
Symphysurina
Strigigenalis caudata
(`Peltabellia
sp.')
Benthamaspis
gibberula
(Not zoned)
Ross (1951);
Hintze (1953, 1973)
Ibex-Utah, USA
Trilobite
zones
L
O
J
H
G
E/F
B
I
Cassinian
Jeffersonian
Demingian
Gasconadian
Stage
North
America
Unit A
Unit B
Unit C
Unit D
Vega Sund
Kong Oscar Fjord
Fig. 3. Plateau of Ella Ø
showing the lower part of
section 4 looking north-
east. The banded unit to
the left is Unit B, which is
succeeded by Unit C.
Camp (in circle) for scale.
GSB191-Indhold 13/12/02 11:32 Side 119
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placed the lowermost c. 50 m of his Cape Weber For-
mation within the Rossodus manitouensis Zone, which
is Tremadoc (Gasconadian­Demingian) in age. However,
this packet of carbonate sediments occurs below the
extensive disconformity recognised by Stouge et al.
(2001; Fig. 2), and on lithological criteria these older
sediments are better placed within the Antiklinalbugt
Formation.
Unit B
Unit B is 250 m thick. The lower part consists of periti-
dal cycles composed of well-bedded bioturbated and sty-
lonodular limestones, thrombolitic mounds and thinly
bedded, laminated dolomitic limestones; ostracodes and
trilobites are recorded. The upper part of Unit B is char-
acterised by bedded, bioturbated and peloidal limestones,
mounds and abundant brown-weathering chert nodules.
The chert nodules are stratabound and richly fossilifer-
ous; coiled and straight cephalopods are common.
The lower part of Unit B belongs to the conodont
Fauna D of Ethington & Clark (1971), whereas the upper
cherty part of Unit B is included in the Oepikodus com-
munis Zone (Smith 1991; Boyce & Stouge 1997). The
Strigigenalis brevicaudata trilobite zone extends into
the lower portion of Unit B, whereas the upper part of
the unit is in the Strigigenalis caudata Zone.
Unit C
Unit C is 330 m thick and composed of thick-bedded,
grey to dark grey peloidal and bioturbated packstone
120
D
A
CW
NS
T
Fig. 5. Stromatolite and thrombolite
mounds from Unit A, Cape Weber
Formation, Ella Ø.
GSB191-Indhold 13/12/02 11:33 Side 120
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to grainstone associated with mounds and closely
spaced, stratabound nodular chert. The macrofauna is
rich and varied and often silicified. Faunal elements
include brachiopods, trilobites, gastropods, cephalopods,
crinoids and sessile insertae sedis, possibly represen-
tative of sponges. The trilobite fauna indicates equiva-
lence with the S. caudata Zone or perhaps the Bentham-
aspis gibberula Zone. The conodont fauna is sparse and
corresponds to the upper part of the O. communis Zone
(Smith 1991; Boyce & Stouge 1997).
Unit D
Unit D, about 460 m thick, is composed of grey lime
mudstone and peloidal limestone, dark bituminous
mudstone and peloidal, thickly bedded, bioturbated
carbonates with minor dolomitic horizons containing
chert. A characteristic marker bed about 100 m from the
top of the unit is composed of thrombolites and stro-
matolites with grainstone intrabeds. The marker hori-
zon is overlain by medium-bedded wackestone and
peloidal lime mudstones and dolomitic bioturbated
limestone associated with chert. The macrofauna is
highly diverse and rich below the local marker horizon,
and cephalopods are common (Fig. 6). The trilobites
are assigned to the Benthamaspis gibberula Zone, which
is coeval with Zones H and I sensu Ross (1951) and
Hintze (1953, 1973) of the Utah­Nevada sections (Boyce
& Stouge 1997). It is possible, however, that Unit D
may be as young as Zone J (= Pseudocybele nasuta Zone
of Fortey & Droser 1996) of the Utah­Nevada succes-
sions. The conodont fauna (Stouge 1978; Smith 1991)
121
D
T
Fig. 4. Section 5 in Antiklinalbugt on the southern side of Ella
Ø. Devonian clastic rocks at right unconformably overlie the
Middle Ordovician Narwhale Sound Formation.
A: Antiklinalbugt Formation
CW: Cape Weber Formation
NS: Narwhale Sound Formation
D: Devonian
T: 1047 m above sea level
Fig. 6. Straight silicified cephalopod from
Unit D, Cape Weber Formation, Ella Ø.
GSB191-Indhold 13/12/02 11:33 Side 121
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is abundant and highly diverse, and is referred to the
Jumodontus gananda ­ ?Reutterodus andinus Interval
of Ethington & Clark (1981). In the uppermost 100 m
of the unit (above the grainstone marker horizon) the
conodont fauna is, however, of low diversity and not
biostratigraphically distinctive (Smith 1991).
Narwhale Sound Formation
On Ella Ø the Narwhale Sound Formation was only
studied in section 4 (Fig. 1); in section 5 many closely
spaced and nearly coast-parallel faults disrupt the suc-
cession. The sediments comprise sucrosic dolostones
with a vuggy texture, and no original sedimentary struc-
tures are preserved.
The base of the Narwhale Sound Formation is
recorded as a prominent 7 m thick bed of laminated
and cross-bedded dolostone and dolomitic bioturbated
limestone. The remainder of the 260 m thick succes-
sion consists of pale grey to cream grey microcrystalline
to sucrosic dolostone, pale grey to grey fine-grained
dolomitic limestone and pale grey limestone. Small
thrombolitic mounds are present and cross-bedding is
common. Individual beds vary in thickness from 5 cm
to over 7 m. Throughout the formation beds of brown
to black cherts and chert-like silicified dolostones occur.
The upper boundary is the Devonian unconformity.
Silicified macrofossils are present. The fauna pri-
marily consists of gastropods, cephalopods and occa-
sional brachiopods, sponges and trilobites.
Conodonts recorded from the upper part of the for-
mation are Middle Ordovician in age (Smith & Bjerreskov
1994), and the Lower to Middle Ordovician boundary
is probably within the lower part of the Narwhale Sound
Formation (Fig. 2; Stouge 1978; Smith 1991).
Albert Heim Bjerge
The Albert Heim Bjerge are bounded by Wordie
Gletscher to the north-east and Reservatet to the north
(Fig. 1). The major E­W-trending valley of Promenadedal
and the river Vibeke Elv form the southern limit of the
study area (Fig. 1). The area is noted for the exposures
of the Middle Ordovician Heimbjerge Formation, which
is the youngest preserved pre-Caledonian unit in this
part of North-East Greenland (Bütler 1940; Cowie &
Adams 1957; Frykman 1979). As is the case on Ella Ø,
Devonian clastic sediments unconformably overlie the
Ordovician rocks.
Investigations in the Albert Heim Bjerge area were
focused on the `Black Limestones' of the Cape Weber
Formation and the type area of the Heimbjerge
Formation (Fig. 1, section 6; Cowie & Adams 1957).
Cape Weber Formation
Cowie & Adams (1957) subdivided the Cape Weber
Formation in the Albert Heim Bjerge into `Lower
Limestones', `Black Limestones', `Upper Limestones' and
`Dolomites and Dolomitic Limestones'. The `Black
Limestones' facies has so far only been distinguished
in the Albert Heim Bjerge area (Cowie & Adams 1957),
where it is 80
-
100 m thick and consists of black, bitu-
minous wackestone to grainstone with shaly partings,
and with chert in the upper part. Fossils are common
and trilobites, including a species of the cosmopolitic
genus Carolinites, have been reported (Cowie & Adams
1957). In 2001 macrofossils were collected from the
`Black Limestones', and samples were collected through-
out the unit for conodont studies.
The `Black Limestones' represent a deep-water marine
incursion on the outer margins of the platform of North-
East Greenland. On Ella Ø the coeval interval may be
either the dark limestones and cherts of the upper part
of Unit C, or the dark bituminous limestones of Unit D.
Heimbjerge Formation
The basal 10­15 m of the Heimbjerge Formation are
dominated by brown and dark red laminated lime mud-
stones with birds-eye structures, stromatolites and bio-
turbated limestones. Above follows c. 50 m of laminated,
grey brown lime mudstone with intraclast conglomer-
ates overlain by platy carbonate mudstones with thin
layers of calcite. A further 10 m are represented by a
heterogeneous succession of massive and platy lime-
stones, in places bioturbated, and marked by the devel-
opment of small stromatoporoid mounds. Thick beds
of light grey, bioturbated clean wacke- to grainstones
with discontinuous horizons of chert nodules occur
throughout the overlying 80 m of section. The highest
exposed 50 m comprise a platy limestone facies dom-
inated by the development of stromatoporoid bioherms.
The preserved succession of the Heimbjerge Formation
is only 300 m at the type locality in Albert Heim Bjerge,
but Frykman (1979) recorded more than 1200 m of
strata belonging to the formation on C.H. Ostenfeld
Nunatak about 25 km to the north (Fig. 1). The
Heimbjerge Formation is Whiterockian in age (Middle
Ordovician; Smith & Bjerreskov 1994).
122
GSB191-Indhold 13/12/02 11:33 Side 122
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Thermal and burial history of the Ella
Ø succession
Smith (1991) briefly reported on the conodont alteration
indices (CAI; Epstein et al. 1977) from the upper Lower
to Middle Ordovician rocks of the study area. Low val-
ues (CAI 1­1.5) are characteristic for the study area, and
higher values (CAI 2) are found in the C.H. Ostenfeld
Nunatak succession to the north (Smith 1991). The pro-
visional results of CAI studies on samples collected in
2000 and 2001 are reported below.
The sequential change in colour of conodont elements
reflects the progressive and irreversible alteration of
organic matter preserved in the conodont elements in
response to temperature, usually a consequence of
thickness of overburden. The CAI values 1­5 have been
experimentally calibrated with temperature ranges and
correlated with other indices of organic metamorphism
by Epstein et al. (1977). Thus, CAI 1 (50­80°C) and CAI
1.5 (50­90°C) are unaltered to nearly unaltered pale-
yellow to yellow conodont elements, CAI 2 (60­140°C)
are yellow to light brown, whereas CAI 3 (110­200°C)
comprises brown altered conodont elements.
CAI determinations from limestones of the Antiklinal-
bugt Formation on Ella Ø give values of CAI 3 decreas-
ing upwards to CAI 1.5 in the Cape Weber Formation
and CAI 1 in the Middle Ordovician Narwhale Sound
Formation. In Albert Heim Bjerge, CAI values are about
CAI 1 in the Heimbjerge Formation. The CAI values
recorded from the Ordovician succession on Ella Ø
suggest that increased depth of burial was the major
factor for the organic metamorphism and that the sub-
sidence in the study area occurred during the Early
Palaeozoic.
A conservative estimate of the overburden respon-
sible for the low CAI values in the Narwhale Sound
Formation on Ella Ø and the Heimbjerge Formation in
Albert Heim Bjerge is about 1.5 to 1.7 km. Thus, 1­1.5 km
of strata of the formerly overlying carbonate sequence
has been removed from the area between Albert Heim
Bjerge and Ella Ø. It follows that the 1200 m thick
sequence of the Heimbjerge Formation reported from
C.H. Ostenfeld Nunatak by Frykman (1979) is virtually
complete. Overburden estimates are based on the geo-
thermal gradient estimates by Rasmussen & Smith (2001)
in the Ordovician carbonates of the northernmost East
Greenland Caledonides and the estimates of heat flow
by Armstrong et al. (1994).
Synthesis
The summer of 2001 was devoted mainly to the Ordo-
vician succession overlying the disconformity separat-
ing the Antiklinalbugt Formation and the Cape Weber
Formation (Stouge et al. 2001). The hiatus corresponds
to all of the Demingian Stage and the early part of the
Jeffersonian Stage of the Canadian Series (Fig. 2).
Faunal evidence from the Cape Weber Formation
shows that the four informal units (A­D) represent most
of the Jeffersonian and the Cassinian stages of the upper
Canadian Series. The Canadian­Whiterockian Series
boundary is apparently conformable and can be placed
within the lower part of the Narwhale Sound Formation.
The Heimbjerge Formation is Whiterockian in age, and
sedimentary sequences younger than Whiterockian have
not been recorded from the study area.
The Ordovician strata below the Demingian discon-
formity have conodonts with CAI values of about 3, sug-
gesting that organic maturity had been reached. The
overlying strata of the upper Canadian ­ lower White-
rockian above the disconformity are organically mature
to immature with CAI values 1.5 to 1.
The upper Lower Ordovician ­ lower Middle Ordovician
Cape Weber Formation and Narwhale Sound Formation
represent a cycle of sedimentation beginning with sub-
tidal facies and concluding with peritidal facies. There
is a change from deposition on a slow subsiding pas-
sive margin to a faster subsiding margin characterised
by rapid accumulation of carbonates. The cycle con-
cluded with a regression in early Whiterockian time.
The `Black Limestones' of Albert Heim Bjerge and the
coeval strata on Ella Ø possibly mark the global sea-level
rise corresponding to the `evae' transgression (= zones
H­I), which is the highest sea-level stand in the Early
Ordovician (Stouge 1982; Barnes 1984; Fortey 1984;
Nielsen 1992). This sea-level rise can be traced in coeval
shelf and slope deposits along the margins around the
Laurentian palaeocontinent (Barnes 1984), and is char-
acterised by the appearance of marginal shelf to slope
faunal elements in the shallow-water carbonates on the
shelf. A second sea-level rise may also be reflected by
the `Black Limestones' that correspond to Zone J of the
upper Canadian Series. In Greenland, this younger sea-
level rise has been recorded from the Nunatami
Formation in North-West Greenland (i.e. the `Bifidus'
shale of Poulsen 1927) and has also been recognised
in western and central North Greenland (Higgins et al.
1991). In western Newfoundland the sea-level rise has
been identified on the basis of faunal evidence (Boyce
et al. 2000).
123
GSB191-Indhold 13/12/02 11:33 Side 123
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The Heimbjerge Formation comprises a second car-
bonate depositional cycle characterised by shallow-
marine subtidal facies. Carbonate accumulation kept
pace with sea-level change. The diverse metazoan fauna
(stromatoporoids) suggests that clear water and high-
energy environments prevailed.
Acknowledgements
The research project is supported by the Danish Natural Science
Research Council (Grant no. 9901696). Helicopter transport was
funded by the National Geographic Society, Washington D.C., USA.
The project represents an inter-disciplinary co-operation
between GEUS, the Geological Survey Division of the Government
of Newfoundland and Labrador, Canada, the Geological Museum,
Copenhagen, Denmark and the Holbaek College of Education,
Denmark. Logistics for this season were organised by T.I. Hauge
Andersson of the Danish Polar Center (DPC). The support of
Sebastian Rasmussen (DPC) in the field is greatly appreciated.
The Sirius Patrol personnel at Ella Ø are thanked for their help
and hospitality.
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Authors' addresses
S.S., Geological Survey of Denmark and Greenland, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. E-mail: ss@geus.dk
W.D.B. & I.K., Government of Newfoundland and Labrador, Mines and Energy, Geological Survey Division, Regional Geology Section,
P.O. Box 8700, St. John's, Newfoundland, Canada A1B 4J6.
J.L.C., Holbaek College of Education, Seminarieparken 2, Holbæk, DK-4300 Denmark.
D.A.T.H., Geological Museum, University of Copenhagen, Øster Voldgade 5­7, DK-1350 Copenhagen K, Denmark.
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